1. Field of the Invention
The present invention relates to surgical instruments and the use thereof, in particular to an ulna cutting jig and its method of use as a guide for obliquely cutting an ulna during surgery to correct ulnar impaction syndrome.
2. Description of the Related Art
There are a variety of surgical instruments present in the art which are designed to guide surgeons when cutting and shaping bone. Due to the unique nature of the human body, surgical instruments often must be specifically designed for particular surgical procedures. Currently there are no known surgical instruments designed for the present novel method of ulnar impaction surgery.
The long oblique ulna shortening osteotomy (LOUSO) jig is an improvement on the current state of the art treatment for ulnar impaction syndrome. Ulnar impaction syndrome is a condition in which the ulna bone is longer than the radius bone, resulting in impaction of the carpal bones on the distal end of the ulna at the wrist joint. Without surgery this condition will lead to the wearing away of the cartilage between the ulna bone and several carpal bones, causing permanent arthritis.
The current surgical technique for correcting ulnar impaction syndrome is referred to as the plating technique and calls for the removal of a wafer of bone, e.g., a disk shaped section of bone, from the ulna, thereby shortening the overall length of the bone. The two remaining pieces of ulna must then be pulled together and secured with a plate spanning the cut which is affixed to the proximal and distal ulnar pieces with several screws.
There are several significant drawbacks with the plating technique. First, the wafer must be exactly the thickness of the desired amount of shortening. Any sizing mistakes are exceedingly difficult, if not impossible, to correct. Second, healing can be unreliable due to the short cross-section and small surface area of bone that must knit together. Insufficient healing can result in long periods of disability, and at times a second surgery involving a bone graft from the pelvis to stimulate bone regrowth. Third, the plate used to secure the ulna together after surgery is often prominent and painful. Many patients require plate removal after the bone has healed. This additional surgery can be expensive, exposes the patient to additional pain and suffering, and the ulna may even fracture during the period of healing after plate removal.
U.S. Pat. No. 5,413,579 discloses a surgical saw guide and drill guide. The saw guide differs from the present invention in that the portion of the saw guide that actually guides a saw blade is very thin as opposed to the guide surface on the present invention, which has much thicker guide surface and provides a much more accurate cut. The ""579 saw guide has a seat formation which is formed by a semicylindrical channel, or a portion of semicylindrical channel, having a convex outer side and a concave interior surface, whereas the present invention is formed from a rectangular block with a concave surface milled to conform to the bone and with an oblique cut defining a triangular shape and providing a relatively thick guide surface for the saw blade. The present invention is also specifically designed to attach to the human ulna, and to guide a surgeon when making oblique cuts in the ulna. whereas the saw guide in the ""579 patent is designed to correct angular deformities in tubular bones. The ""579 invention is not designed, as is the present invention, to extend past the edge of the bone to be cut. This extended portion insures a straight cut all the way through the bone.
U.S. Pat. No. 5,779,709 discloses an ulnar alignment system. This system is designed to provide precision cuts in the proximal portion of the ulna in order to assist in total elbow arthroplasty. The ""709 patent is distinguishable because it cannot be used to perform the oblique cuts needed to correct ulnar impaction syndrome using the apparatus and method of the present invention.
U.S. Pat. No. 5,817,097 discloses a bone saw blade guide with a magnet. This device is designed to allow a surgeon to produce precision cuts on the distal end of a femur when performing a knee replacement operation. The bone saw blade guide disclosed in this invention cannot be adapted to produce the oblique cuts on a ulna that are made possible with the present invention.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a long oblique ulna shortening osteotomy jig solving the aforementioned problems is desired.
The long oblique ulna shortening osteotomy (LOUSO) jig has a flat top surface which is shaped like a substantially right triangle, a concave bottom surface which is also shaped like a substantially right triangle, a flat hypothenuse side surface, and two flat leg side surfaces. The jig has two holes defined therein extending from the top surface to the bottom surface.
The jig is used in connection with a novel method of ulnar impaction corrective surgery. The first step of the surgical method involves securing the jig to the ulna being resized. The concave bottom surface of the jig rests against the corresponding convex surface of the ulna. The jig is secured to the ulna through the use of two surgical screws.
The next step in the surgical method is that the ulna must be severed with a single long oblique cut. The flat hypothenuse side surface of the jig is used to guide a surgical bone saw while making the long oblique cut to insure that the cut is perfectly straight.
Once the cut is made the ulna will be rendered into proximal and distal pieces. The distal piece will then be moved toward the proximal piece with the cut portions sliding past one another such that the overall length of the ulna is reduced by an amount sufficient to correct the ulnar impaction. The proximal and distal ulnar pieces will then be affixed to one another using a number of surgical screws positioned along the cut portion.
Accordingly, it is a principal object of the invention to provide a device and method of use of the device which functions to allow a surgeon to accurately produce a single long oblique cut across the ulna in a surgical procedure to correct ulnar impaction syndrome.
It is another object of the invention to provide a device and method of using the device which will allow for a quicker recovery from ulnar impaction syndrome surgery than conventional methods.
It is a further object of the invention to provide a device and method using the device which functions to obviate the need for a plate to secure the proximal and distal portions of the ulna after surgery for correction of ulnar impaction syndrome.
Still another object of the invention is to provide a surgical device and method of using the device which will function to allow for a diminished risk of infection and more consistent positive results in surgery for repair of ulnar impaction.
It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.